Exercise guidelines for women with Type 1 diabetes due for an overhaul

A Type 1 diabetes diagnosis at 15 didn’t stop Saru Toor from playing competitive handball. But figuring out how to adjust her insulin before games and practices was stressful, she says. There was always a risk that her blood sugar would bottom out.

So, she jumped at the chance to take part in a study on how to help menstruating women manage the risks of developing low blood glucose levels during exercise. If not managed properly, the condition — called hypoglycemia — can lead to coma or even death.

“I want there to be more knowledge about all of this for other Type 1 diabetics, especially those who experience having a menstrual cycle and what that does to their blood sugar,” says Toor. Now 22 and a lab assistant at the University of Alberta, she still exercises regularly but avoids certain days of her cycle.

About five to 10 per cent of the 1.6 million women in Canada who live with diabetes have Type 1, which happens when the pancreas stops producing insulin.

The study, funded by a WCHRI Innovation Grant, was the first to examine the effect on blood sugar during exercise throughout the menstrual cycle of women with Type 1 diabetes. It was led by Jane Yardley, an adjunct kinesiology professor at the U of A and director of the research unit in physical activity and diabetes at the Montreal Clinical Research Institute.

Yardley doesn’t want fear of hypoglycemia to stop women from exercising. So, her research is focused on developing more precise recommendations for adjusting insulin.

Guidelines exist, but they’re based on data from studies on young, fit men, she says. “Women have been completely neglected in this field.”

Exercise is important for people with Type 1 diabetes, which requires insulin therapy for life. It can prevent or delay the progression of some diabetes-related complications, and studies show that those who exercise regularly live several years longer than those who don’t. But it’s especially crucial for women with the life-altering autoimmune disease, because they lose more muscle mass and bone density after menopause and suffer up to four times the risk of fractures than women without diabetes.

In a second project, initially supported by a WCHRI Bridge Grant and now funded by Diabetes Canada, Yardley is looking at how to manage the risks of developing low blood sugar during exercise in post-menopausal women with Type 1 diabetes.

Her studies began when she was based at the U of A and continued in Montreal after she moved there in 2023.

Although results are not yet published, Yardley is already talking to diabetes educators and nurses about adjusting insulin differently depending on where a woman is in her menstrual cycle. Early results indicate some have a higher risk of hypoglycemia during the luteal phase, a week or so before bleeding. But that doesn’t mean they should avoid exercise, Yardley says.

“I would never say that,” she laughs. “I would say, ‘pay more attention’… If you’re aware, you can pre-empt.”